def cry(self, theta, q_control, q_target):
"""
Apply Controlled-RY (cry) Gate.
Args:
self (QuantumCircuit): The circuit to apply the ch gate on.
theta (float): The rotation angle.
q_control ((QuantumRegister, int)): The control qubit.
q_target ((QuantumRegister, int)): The target qubit.
"""
if not is_qubit(q_control):
raise AquaError('A qubit is expected for the control.')
if not self.has_register(q_control[0]):
raise AquaError('The control qubit is expected to be part of the circuit.')
if not is_qubit(q_target):
raise AquaError('A qubit is expected for the target.')
if not self.has_register(q_target[0]):
raise AquaError('The target qubit is expected to be part of the circuit.')
if q_control == q_target:
raise AquaError('The control and target need to be different qubits.')
self.u3(theta / 2, 0, 0, q_target)
self.cx(q_control, q_target)
self.u3(-theta / 2, 0, 0, q_target)
self.cx(q_control, q_target)
return self
def ch(self, q_control, q_target):
"""
Apply Controlled-Hadamard (ch) Gate.
Note that this implementation of the ch uses a single cx gate,
which is more efficient than what's currently provided in Terra.
Args:
self (QuantumCircuit): The circuit to apply the ch gate on.
q_control ((QuantumRegister, int)): The control qubit.
q_target ((QuantumRegister, int)): The target qubit.
"""
if not is_qubit(q_control):
raise AquaError('A qubit is expected for the control.')
if not self.has_register(q_control[0]):
raise AquaError(
'The control qubit is expected to be part of the circuit.')
if not is_qubit(q_target):
raise AquaError('A qubit is expected for the target.')
if not self.has_register(q_target[0]):
raise AquaError(
'The target qubit is expected to be part of the circuit.')
if q_control == q_target:
raise AquaError('The control and target need to be different qubits.')
self.u3(-7 / 4 * pi, 0, 0, q_target)
self.cx(q_control, q_target)
self.u3(7 / 4 * pi, 0, 0, q_target)
return self
def rcccx(self, q_control_1, q_control_2, q_control_3, q_target):
"""
Apply 3-Control Relative-Phase Toffoli gate from q_control_1, q_control_2, and q_control_3 to q_target.
The implementation is based on https://arxiv.org/pdf/1508.03273.pdf Figure 4
Args:
self (QuantumCircuit): The QuantumCircuit object to apply the rcccx gate on.
q_control_1 (tuple(QuantumRegister, int)): The 1st control qubit.
q_control_2 (tuple(QuantumRegister, int)): The 2nd control qubit.
q_control_3 (tuple(QuantumRegister, int)): The 3rd control qubit.
q_target (tuple(QuantumRegister, int)): The target qubit.
"""
if not is_qubit(q_control_1):
raise AquaError('A qubit is expected for the first control.')
if not self.has_register(q_control_1[0]):
raise AquaError(
'The first control qubit is expected to be part of the circuit.')
if not is_qubit(q_control_2):
raise AquaError('A qubit is expected for the second control.')
if not self.has_register(q_control_2[0]):
raise AquaError(
'The second control qubit is expected to be part of the circuit.')
if not is_qubit(q_target):
raise AquaError('A qubit is expected for the target.')
if not self.has_register(q_target[0]):
raise AquaError(
'The target qubit is expected to be part of the circuit.')
self._check_dups([q_control_1, q_control_2, q_control_3, q_target])
_apply_rcccx(self, q_control_1, q_control_2, q_control_3, q_target)
def mct(self, q_controls, q_target, q_ancilla, mode='basic'):
"""
Apply Multiple-Control Toffoli operation
Args:
q_controls: The list of control qubits
q_target: The target qubit
q_ancilla: The list of ancillary qubits
mode (string): The implementation mode to use
"""
if len(q_controls) == 1: # cx
self.cx(q_controls[0], q_target)
elif len(q_controls) == 2: # ccx
self.ccx(q_controls[0], q_controls[1], q_target)
else:
# check controls
if isinstance(q_controls, QuantumRegister):
control_qubits = [qb for qb in q_controls]
elif isinstance(q_controls, list):
control_qubits = q_controls
else:
raise AquaError(
'MCT needs a list of qubits or a quantum register for controls.'
)
# check target
if is_qubit(q_target):
target_qubit = q_target
else:
raise AquaError('MCT needs a single qubit as target.')
# check ancilla
if q_ancilla is None:
ancillary_qubits = []
elif isinstance(q_ancilla, QuantumRegister):
ancillary_qubits = [qb for qb in q_ancilla]
elif isinstance(q_ancilla, list):
ancillary_qubits = q_ancilla
else:
raise AquaError(
'MCT needs None or a list of qubits or a quantum register for ancilla.'
)
all_qubits = control_qubits + [target_qubit] + ancillary_qubits
self._check_qargs(all_qubits)
self._check_dups(all_qubits)
if mode == 'basic':
_ccx_v_chain(self, control_qubits, target_qubit, ancillary_qubits)
elif mode == 'advanced':
_multicx(self, [*control_qubits, target_qubit],
ancillary_qubits[0] if ancillary_qubits else None)
elif mode == 'noancilla':
_multicx_noancilla(self, [*control_qubits, target_qubit])
else:
raise AquaError(
'Unrecognized mode for building MCT circuit: {}.'.format(mode))
def mcry(self, theta, q_controls, q_target, q_ancillae):
"""
Apply Multiple-Control RY (mcry) Gate.
Args:
self (QuantumCircuit): The circuit to apply the ch gate on.
theta (float): The rotation angle.
q_controls (QuantumRegister | (QuantumRegister, int)): The control qubits.
q_target ((QuantumRegister, int)): The target qubit.
q_ancillae (QuantumRegister | (QuantumRegister, int)): The ancillary qubits.
"""
# check controls
if isinstance(q_controls, QuantumRegister):
control_qubits = [qb for qb in q_controls]
elif isinstance(q_controls, list):
control_qubits = q_controls
else:
raise AquaError(
'The mcry gate needs a list of qubits or a quantum register for controls.'
)
# check target
if is_qubit(q_target):
target_qubit = q_target
else:
raise AquaError('The mcry gate needs a single qubit as target.')
# check ancilla
if q_ancillae is None:
ancillary_qubits = []
elif isinstance(q_ancillae, QuantumRegister):
ancillary_qubits = [qb for qb in q_ancillae]
elif isinstance(q_ancillae, list):
ancillary_qubits = q_ancillae
else:
raise AquaError(
'The mcry gate needs None or a list of qubits or a quantum register for ancilla.'
)
all_qubits = control_qubits + [target_qubit] + ancillary_qubits
self._check_qargs(all_qubits)
self._check_dups(all_qubits)
self.u3(theta / 2, 0, 0, q_target)
self.mct(q_controls, q_target, q_ancillae)
self.u3(-theta / 2, 0, 0, q_target)
self.mct(q_controls, q_target, q_ancillae)
return self
